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A metal tube is cold formed into a stamped member by tube is cold formed into a stamped member by sealing a tube containing liquid at approximately atmospheric pressure and then stamping the liquid-filled tube in a die. The pressure within the tube increases during the stamping step to force the wal

A metal tube is cold formed into a stamped member by tube is cold formed into a stamped member by sealing a tube containing liquid at approximately atmospheric pressure and then stamping the liquid-filled tube in a die. The pressure within the tube increases during the stamping step to force the walls of the tube to conform to the die cavity, eliminating the need to pressurize the tube prior or subsequent to stamping.

대표청구항 ▼

A process for cold forming a metal tube comprising the steps of: filling a tube with a liquid; sealing the tube with at least one cap having a pair of relief valves, one relief valve relieving liquid from the tube at approximately static pressure and the other relief valve relieving liquid from the

A process for cold forming a metal tube comprising the steps of: filling a tube with a liquid; sealing the tube with at least one cap having a pair of relief valves, one relief valve relieving liquid from the tube at approximately static pressure and the other relief valve relieving liquid from the tube at a stamping pressure substantially above static pressure, said sealing step forming a sealed tube having a given interior volume and confining the liquid within the sealed tube at approximately atmospheric pressure, the one relief valve permitting excess liquid to exit the tube during the sealing step; stamping the sealed tube in a die having a die cavity of a given interior configuration to form a stamped member having an exterior configuration conforming to the interior configuration of the die cavity and having an interior volume no greater than the interior volume of the sealed tube; releasing a volume of the liquid from within the sealed tube during the stamping operation approximately equal to the difference between the interior volume of the sealed tube and the interior volume of the stamped member, the other relief valve permitting the volume of liquid to exit the tube during the stamping step; and removing the cap and draining from within the stamped member the liquid remaining after the stamping step.